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How do I get HTTP headers using HttpClient HEAD request?

The HTTP HEAD method is used for reading the headers information of a resource returned when accessing it using the HTTP GET method. Such request can be done before deciding to download a large resource to save bandwidth. The response to a HEAD method should not have a body, in the code below we use the HttpResponse.BodyHandlers.discarding(), which is a response body handler that discards the the response body.

In the code snippet below we start by creating an instance of HttpClient, in this example we use the HttpClient.newBuilder().build() method. After creating the HttpClient we create the HttpRequest object. We set the HTTP method to HEAD by calling the method method() and pass a string “HEAD” as the method name and HttpRequest.BodyPublishers.noBody() a request body publisher which sends no request body.

The next step in the code below is to send the request and get the response headers from the HttpResponse object using the headers() method. The map() method of the HttpHeaders object give us a key-values of the headers returned by the server.

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